1. Field of the Invention
Methods and apparatuses consistent with exemplary embodiments relate to a print controlling apparatus, an image forming apparatus, and a method of forming an image, and more particularly, to a print controlling apparatus, an image forming apparatus, and a method of forming an image using draft-printing.
2. Description of the Related Art
Modern print controlling apparatus and image forming apparatus have a so-called “draft-print” mode. The draft-print mode reduces quality of texts and images, but can save resources such as toner (ink). The draft-print technology generates print data for draft-printing in the print controlling apparatus and the image forming apparatus
The print data may be expressed in a metafile format or a page description language (PDL). Microsoft enhanced metafile (EMF) is the representative of the print data of the metafile format. PostScript and PCL are examples of the PDL. A PDF format, which is intended to describe an original printing page, may be used as metafiles of various formats according to various operating systems.
The PDL and the metafile of various formats include a record (referred to as a “tag” or “command”) indicating text data, bitmap image data, and vector graphics data. The printing page is changed by means of each metafile or PDL record (command). By this approach, a printing process may be controlled in the draft print mode.
A related-art technology is based on selective data pre-processing according to a type of data. For example, U.S. Patent Application Publication No. 20100214614 describes “contextual rendering” of “print elements”. Similar approaches are described in U.S. Patent Application Publication Nos. 20100128287, 20050063749, and 20090290883.
Another approach is proposed in U.S. Patent Application Publication No. 20090195811. This approach configures content-based skipping of objects excluding all of these objects in a printing process.
However, there are problems in the related-art technology. In particular, as a rule, the draft-printing method is based on reduction in density of elements for expressing an image, which results in deterioration in image quality. Such related-art methods may cause great waste of toner since these methods paint images on a pixel area basis.
To solve these problems, draft-printing is performed using a sketch image. The sketch image refers to an image that looks like a picture drawn with a pencil. If draft printing is performed using the sketch image, visual quality of the original image is improved and sense of reality is not reduced so much.
In order to convert an image into such a sketch image, a picture included in a printing page is expressed by vector graphical elements. These elements are separable. In this case, it is impossible to process a whole image directly.
That is, in the related-art methods, problems arise if data which looks like a “picture” is represented after being wholly rasterized, being converted into a set of individual graphical elements, or being converted into vector graphical elements. That is, if a picture is represented as a set of independent elements, theses data cannot be processed as an integral picture. Since the data is applied to the picture as a whole rather than as individual elements, most of the toner-saving rules proposed in the above-mentioned patent applications is useless in this case.
Also, vector-based composite graphics may cause problems in an application of independent image printing rules, and also, a similar problem arises when one tries to convert such composite graphics into a sketch image.
The conversion into the sketch image is not applied to a primitive represented by a small rasterized image, that is, a line with one pixel width. That is, since the conversion into the sketch image is applied to only the whole picture, there is a demand for a method for combining graphical primitives into a group in order to generate a picture with the graphical primitives.